1. Field of the Invention
This invention relates to a disc cartridge for rotatably housing a disc-shaped recording medium, such as a magnetic disc.
2. Description of Related Art
Up to now, a disc cartridge having a magnetic disc as an information recording medium housed therein has generally been used for an electronic equipment, such as a computer. This disc cartridge is now explained by referring to the drawings.
This disc cartridge is comprised of a magnetic disc rotatably housed within a main cartridge body portion 103 made up of an upper cartridge half and a lower cartridge half combined together, as shown in FIGS. 1 to 5. In this main cartridge body portion 103 is formed a recording/reproducing aperture, not shown, faced by a recording/reproducing head provided on a recording/reproducing apparatus 110, as later explained, in adjacency to the front end faced by the recording/reproducing apparatus 110, and a shutter member 107 is arranged for opening/closing the recording/reproducing aperture, as shown in FIGS. 1 and 2.
The main cartridge body portion 103 of the disc cartridge 101 has a pre-set longitudinal size L in a direction parallel to the direction of insertion into the recording/reproducing apparatus 110 and a pre-set width W and a pre-set thickness (height) H in a direction perpendicular to the direction of insertion, as shown in FIGS. 3 to 5.
The recording/reproducing apparatus 110, into which is inserted the above-described disc cartridge 101, is now explained by referring to FIGS. 6 to 9. This recording/reproducing apparatus 110 includes a substantially rectangular cartridge inserting aperture 110a, into which is inserted the disc cartridge 101, as shown in FIG. 6. This cartridge inserting aperture 110a has a pre-set width W.sub.D and a pre-set height H.sub.D, as shown in FIG. 6. In an opening portion is mounted a lid 110b for opening/closing the opening portion.
Referring to FIG. 7, the recording/reproducing apparatus 110 has, in the cartridge loading portion for loading the disc cartridge 101 therein, a base plate 110c on which is set the disc cartridge 101 inserted from the cartridge inserting aperture 110a, and a holder member 110d in which is housed the inserted disc cartridge 101.
Referring to FIG. 7, when the disc cartridge 101 is inserted from the cartridge inserting aperture 110a, the front surface of the main cartridge body portion compresses against the lid 110b of the recording/reproducing apparatus 110 for pivoting and uplifting the lid 110b in the direction indicated by arrow D in FIG. 7.
Referring to FIG. 8, the disc cartridge 101 inserted from the cartridge inserting aperture 110a of the recording/reproducing apparatus 110 is advanced along a base plate 110c so as to be housed within a holder member 110d. The front surface of the disc cartridge 101 compresses against an abutment surface of the holder member 110d for sliding the holder member 110d in a direction shown by arrow C in FIG. 8.
Referring to FIG. 9, the size of the recording/reproducing apparatus 110 in a direction parallel to the direction of insertion of a cartridge loading section, corresponding to the size between the abutment surface of the holder member 110d and a guide provided at the cartridge inserting aperture 110a, is set to a longitudinal size L.sub.D slightly larger than the longitudinal size L of the disc cartridge 101.
Referring to FIG. 9, when loaded at the pre-set cartridge loading position, the disc cartridge 101 is thrust onto the base plate 110c under the force of a spring 110e provided on the holder member 110d, whilst the holder member 110d and the base plate 110c are moved in the direction indicated by arrow E in FIG. 9 so as to be set on a turntable, not shown. When the disc cartridge 101 is loaded in position, there is maintained a pre-set clearance between its front surface and the abutment surface of the holder member 110d, while there is also maintained a pre-set clearance between its rear surface and the guide of the cartridge inserting aperture 110a.
The disc cartridge 101 has its magnetic disc rotated by the turntable for recording/reproducing information signals on or from the magnetic disc.
With the recent tendency towards multi-media, the information signals being handled, such as picture data or speech data, have become diversified and voluminous. In keeping up with this tendency, the recording capacity of the disc cartridge is also increasing. Thus, it is required of the disc cartridge to be able to record information signals to high density. Specifically, there is currently proposed a large-capacity disc cartridge of an outer size substantially equal to that of a conventional disc cartridge and having the recording capacity for information signals of the order of 120 megabytes (MB).
Since the main cartridge body portion of the large-capacity disc cartridge has the outer size approximately equal to that of the conventional disc cartridge 101, there is a risk of inadvertent insertion of the large-capacity disc cartridge on the recording/reproducing apparatus 101 designed for loading only the conventional low-capacity disc cartridge 101 thereon.
Since the information signals are recorded to high recording density on the large-capacity disc cartridge such that the recording tracks for information signals of the large-capacity disc cartridge are of narrow widths, if such large-capacity disc cartridge is inadvertently loaded on the conventional recording/reproducing apparatus 110 having different specifications, such as recording capacity, there is raised a problem that signal errors be produced, or information signals recorded on the magnetic disc be destroyed.